Caveman,
More important than which specific camera is, I think, to buy from a good dealer so that you can be confident about getting a usable camera. After you have used that one for a while and decided that you need another one, you'll be better prepared to take some chances on ebay.
That said, I strongly recommend two sellers:
Oleg:
http://www.okvintagecamera.com/index.html
Honest, not too pricey, ships quick. There is not always a lot of choice but you can email him and ask about specific models and he'll likely have one.
And Fedka:
http://www.fedka.com/catalog/.
Another excellent seller. For the same reasons as above.
If you know the specific features you want/need; things like slow speeds or not, bottom loading or not, strap lugs or not. Or you just want to get a particular "style", there is a pretty good site that has photos of most of the various FSU(Former Soviet Union) cameras:
http://www.commiecameras.com/.
A good basic overview of what's out there.
My personal choices are the Zorki 3m and the FED5. I have used others but these two are what I end up shooting with. I own and like a Kiev 4a but the lens choices(
not the lenses themselves, just the variety) are better with the Zorki and FED.
Welcome to our obsession!
😀
Rob